I. Field of the Invention
This invention relates generally to locking mechanisms and relates particularly to an apparatus which is locked within the eye of a trailer tongue to prevent the unauthorized movement of the trailer.
II. Description of the Prior Art
There are a number of locks made to secure one item within another to prevent unauthorized use or unauthorized access using a cylinder having tumblers operated by a key. This structure is revealed in U.S. Pat. Nos. Feller, 2,742,726; Kruschwitz, 2,791,976, and Jacobi, 1,982,831.
In U.S. Pat. No. Hudson, 3,884,143, a pintle hook locking device for an eye of a trailer tongue is revealed. This lock requires a separate adjustment for pintle size and provides no protection for the lock cylinder or for forced removal.
In my U.S. Pat. No. 4,196,575, the device provided locking with automatic sizing for a number of ring sizes and continued positive locking even upon the lock cylinder removal.
My present device provides all of these functions in a greatly improved and simplified lock with a consequent reduction in both number of parts and cost of manufacture. The elimination of parts permits the threading members used to attach the two lock parts to be greatly increased in diameter with a corresponding increase in strength. The latching means in this device moves perpendicular to their receptacle as compared to the rotation of the latching means in my previous device which now requires that the entire end of the latch be sheared off to permit removal of the lock without a key.